<template>
  <div class="s-canvas">
    <canvas
        id="s-canvas"
        :width="contentWidth"
        :height="contentHeight"
    ></canvas>
    <div class="text" @click="drawPic">换一张</div>
  </div>
</template>

<script lang="ts" setup>
import {onMounted,watch} from "vue";

const props = defineProps({
  identifyCode: {
    type: String,
    default: "1234",
  },
  fontSizeMin: {
    type: Number,
    default: 30,
  },
  fontSizeMax: {
    type: Number,
    default: 70,
  },
  backgroundColorMin: {
    type: Number,
    default: 255,
  },
  backgroundColorMax: {
    type: Number,
    default: 255,
  },
  colorMin: {
    type: Number,
    default: 0,
  },
  colorMax: {
    type: Number,
    default: 160,
  },
  lineColorMin: {
    type: Number,
    default: 100,
  },
  lineColorMax: {
    type: Number,
    default: 255,
  },
  dotColorMin: {
    type: Number,
    default: 0,
  },
  dotColorMax: {
    type: Number,
    default: 255,
  },
  contentWidth: {
    type: Number,
    default: 220,
  },
  contentHeight: {
    type: Number,
    default: 63,
  },
});
// 生成一个随机数
const randomNum=(min:number, max:number)=> {
  return Math.floor(Math.random() * (max - min) + min);
}
// 生成一个随机的颜色
const  randomColor=(min:number, max:number)=> {
  let r = randomNum(min, max);
  let g = randomNum(min, max);
  let b = randomNum(min, max);
  return "rgb(" + r + "," + g + "," + b + ")";
}

const drawPic=()=> {
  let canvas:any = document.getElementById("s-canvas");
  let ctx = canvas.getContext("2d");
  ctx.textBaseline = "bottom";
  // 绘制背景
  ctx.fillStyle = randomColor(
      props.backgroundColorMin,
      props.backgroundColorMax,
  );
  ctx.fillRect(0, 0, props.contentWidth, props.contentHeight);
  // 绘制文字
  for (let i = 0; i < props.identifyCode.length; i++) {
   drawText(ctx, props.identifyCode[i], i);
  }
  drawLine(ctx);
  drawDot(ctx);
}

const drawText=(ctx:any, txt:string, i:number)=> {
  ctx.fillStyle = randomColor(props.colorMin, props.colorMax);
  ctx.font =
      randomNum(props.fontSizeMin, props.fontSizeMax) + "px SimHei";
  let x = (i + 1) * (props.contentWidth / (props.identifyCode.length + 1));
  let y = randomNum(props.fontSizeMax, props.contentHeight - 5);
  var deg = randomNum(-45, 45);
  // 修改坐标原点和旋转角度
  ctx.translate(x, y);
  ctx.rotate((deg * Math.PI) / 180);
  ctx.fillText(txt, 0, 0);
  // 恢复坐标原点和旋转角度
  ctx.rotate((-deg * Math.PI) / 180);
  ctx.translate(-x, -y);
}

const drawLine=(ctx:any)=> {
  // 绘制干扰线
  for (let i = 0; i < 5; i++) {
    ctx.strokeStyle = randomColor(
        props.lineColorMin,
        props.lineColorMax,
    );
    ctx.beginPath();
    ctx.moveTo(
        randomNum(0, props.contentWidth),
        randomNum(0, props.contentHeight),
    );
    ctx.lineTo(
       randomNum(0, props.contentWidth),
        randomNum(0, props.contentHeight),
    );
    ctx.stroke();
  }
}

const drawDot=(ctx:any)=> {
  // 绘制干扰点
  for (let i = 0; i < 80; i++) {
    ctx.fillStyle = randomColor(0, 255);
    ctx.beginPath();
    ctx.arc(
        randomNum(0, props.contentWidth),
        randomNum(0, props.contentHeight),
        1,
        0,
        2 * Math.PI,
    );
    ctx.fill();
  }
}
onMounted(()=>{
  drawPic();
})
watch(()=>{
 return props.identifyCode
},(n,o)=>{
  console.log("触发了监听，66123")
  drawPic()
})
</script>

<style lang="scss" scoped>

.s-canvas {
  height: 40px;
  display: flex;
  canvas {
     border-radius: 1px;
  }
  .text {
    cursor: pointer;
    font-size: 16px;
    font-family: Microsoft YaHei;
    font-weight: 400;
    color: rgba(255,0,0,1);
    margin-left: 10px;
  }
}

</style>
